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Steps I follow to setup a CI CD workflow. Write Dockerfile in the code repo. Write a k8s Manifest file using kustomize template. Following this tree structure. ├── base │ └── app │ ├── deployment.yaml │ ├── kustomization.yaml │ └── service.yaml └── overlay ├── production │ └── kustomization.yaml └── staging └── kustomization.yaml Write a skaffold file ( skaffold init will auto initialize itself ). Build Docker image and Render the k8s manifest using skaffold. skaffold build && \ skaffold render --digest-source='tag' -p staging -o ../path-to/manifest.yml Manually push the rendered k8s to the manifest repository. Setup the k8s to access the private repository kubectl create secret generic <secret-name> \ --from-file=.dockerconfigjson=~/.docker/config.json \ --type=kubernetes.io/dockerconfigjson Update the K8s manifest with spec: template: spec: imagePullSecrets: - name: <secret-name> Setup argo cd in the target k8s cluster. ArgoCD Getting Started kubectl create namespace argocd kubectl apply -n argocd -f https://raw.githubusercontent.com/argoproj/argo-cd/stable/manifests/install.yaml kubectl patch svc argocd-server -n argocd -p '{"spec": {"type": "LoadBalancer"}}' kubectl -n argocd get secret argocd-initial-admin-secret -o jsonpath="{.data.password}" | base64 -d; echo Login and Link repository to argocd. Create an app in argocd and configure to access the repository and the cluster to deploy.

Programming On a high level, Programming is simply writing instructions to a computer on how to compute or process data and give the desired output, in a programming language. Also, the input and output can be nothing. Either way, a program written involves changing the state of a system. A computer is a state machine and all it does is flip 0s and 1s. These details are abstracted from us as computer science has evolved. ...

Migration in DBMS In an application, It is quite inevitable to have changes on the database. The changes can be on the structure of data or even the data itself. It is a good idea to apply changes to a database as versioned and reversible set of steps. A representation of changes to be done the database can be called Migration. Two types of migration are Schema and Data migrations. ...

Query performance in DBMS When we query a database there are certain operations performed, the main operation to consider is the type of scan it would result in. The performance is calculated based on the time taken to do the operations. Various types of operations have different costs based on disk and CPU usage. Cost can be assumed to be the amount of time taken. Therefore, lower the cost better the performance (faster response from DB) ...

Authorization in Software Systems As we know that, the concept of Autorization is simply checking if a verified user or application is allowed to do something. It generally comes to authorization policies which would be checked to make this decision. The decision is simple, is person X allowed to access resource R ? This can be further broken up to Create, Read, Update, Delete Access. There are multiple patterns to achieve access control in software systems. But generally, the idea is to filter out data that is only accessible to a user. ...

Docker compose is a tool that helps us define and run multiple services together. We declare the services and their attributes in a configuration file and the docker compose tool reads it and issues the command to docker CLI in order to start and run the services. It helps us abstract all the creation of different components, building or pulling images etc… To run multiple services for a project. Once a compose-file is declared, we can run everything all at once with a single run command, we can also manage them via the docker compose interface. ...

Docker images are built from a Dockerfile, which is a blueprint for how to prepare a ready-to-run image. We can relate it to steps we perform in a computer to get something installed and running. We can start with a base image that corresponds to an OS (like ubuntu, alpine, Debian etc…) or we can even start from essentials installed in an OS. Basic steps are Start from the base image Run commands Specify default run command Here’s a basic example from nodejs ...

Docker is a platform that provides lightweight isolated runtimes for software. It helps us to package the software and its dependencies in a ready to run format. We can say its sort of works like VMs except, docker uses the kernel of our base OS. This is achieved by few techniques done with docker, File system snapshot - Dockerfile is used to build a filesystem snapshot that contains all the required files to run the software. Namespacing - Docker isolates the resources for the running processes using the Namespacing feature. It is a linux feature which partitions resources and control access between processes on resources. Control groups - The volume of resources used by a process can also be limited by docker. It is achieved by cgroups features which is another linux feature that helps define resource limits for a process. Why use Docker? As docker enables packaging and running software in a lightweight way, It solves the problem of setting up and configuring an environment to run the software. ...

Indexing data in DBMS Indexing in the database can be similar to an index in front of a book that shows the title and its page number, DB stores these in B-Tree or LSM Tree structures to search through them as fast as possible. Indexing improves the data lookup speed but not always. An index is the fastest when it requires lesser random disk access. We know that the data is stored on disk and therefore, Fragmentation of data is more important in performance. If the required data is scattered in different sections of a disk, it will be slower. ...

Database data storage on disk Database persists information on disk in different forms like flat files, ISAM, heap files etc.. Depending on the Database Engine. In a common scenario, we store some information typed into a text editor by clicking save and choosing a location. Similarly, database saves our data into a configured location, mostly in a bit complicated structure than a text file. Database engines will structure the data and files in different ways to be able to retrieve them faster. ...